Let’s start with the easy part: half of the base is 3.
Therefore, 3 x h + 1 = 18
3 x h = 3h and 3 x 1 = 3
3h + 3 = 18
To solve these equations, you have to do the inverse. First you would need to minus 3:
3h = 15
3h is a simpler way of saying 3 x h, so the inverse would be a divide.
h = 5
